[IN2DEP]

Hey guys

sorry but i have tryed to search for the answer but didnt find what i wanted, anyways ...........
i Just want to confirm it, I have a set of F100 15x7 sunnys and want to run 32"/11.5" wide, will they be to wide for the 7" rim ??

Im going to get BFG KM2s, not much out there in a 32" ey, what other tyre out there can i get thats in a 32" ??
And what do you guys think about the KM2s ?? are they as good as all the magazines say ??

almost got my zook ready guys just a few small things to do

cheers guys keith

[suzukikid]

heapscome in an imperial size.....i would go a silverstone extreme...

[IN2DEP]

suzukikid wrote:

heapscome in an imperial size.....i would go a silverstone extreme...

Thats what your running yes ??

And what is the imperial size for a 32/11.5 15 rim

[monley]

You can get the new MT TTC claws in 32x11.5 r15 GREAT tyre from what i have seen, they bag out really well on a zook to. Also i think 11.5" wide tyres might be to wide for a 7" rim...

[Gwagensteve]

32 11.5 R15 is an imperial size.

An 11.5 should be on an 8" rim.

I clearly don't have the same tyre budget you do - there's no way I'd be spending that much money on road tyres. Whilst the KM2's are an excellent tyre AFAIK, a 32 11.5 is the second worst size you could run on a sierra. (The winner is 33 12.5.)

If you really want to splash out on KM2s, run GV rims and 235 85 16's, which are the same diameter but much narrower, proving you with better grip under all conditions.

PErsonally, I'd run two sets of tyres - 7.50 R16's on LJ rims for tracks and whatever road tyre you like for the rest of the time. Buy smart and you could have both sets for less than the cost of 32" KM2's.

Just my 2C.

Steve.

PS in case you think I am a hypocrite telling you this and running 35 13.5 Krawlers - I can tell you the Krawlers are rubbish on road compared to my 9" wide swampers, and on greasy hills I've seen enough Krawlers to know they are going to suck. The excessive width and sidewall tread is why they work in ruts, and that's mostly where we get stopped, which is why I'm running them.

[IN2DEP]

monkey wrote:

You can get the new MT TTC claws in 32x11.5 r15 GREAT tyre from what i have seen, they bag out really well on a zook to. Also i think 11.5" wide tyres might be to wide for a 7" rim...

What could go wrong or be a problem ?? "I" wouldnt thing 25mm will do much but thats me yeah lol

[Gwagensteve]

We already run narrower rims than recommended for 10.5's - the recommended rein for a 10.5 is an 8, and we all run 7's, so really, an 11.5 on a 7" rim is 50mm narrower than recommended.

Steve.

[christover1]

BFG KM2s come in a 33 x 10.50 x 15
I believe.

[Gwagensteve]

christover1 wrote:

BFG KM2s come in a 33 x 10.50 x 15
I believe.

They do, and that's a very good point. That's 59575856756757X better than a 32 11.5.

[IN2DEP]

christover1 wrote:

BFG KM2s come in a 33 x 10.50 x 15
I believe.

Aswell as a 32" 11.5, i looked it up

and steve thats a very big number you got there lol, why is it so much better ??

[Gwagensteve]

Because 32 11.5 is too short and too fat to have the right shaped footprint. Taller and narrower is always better than shorter and fatter, regardless of car or terrain.

Normally the only disadvantage of recommending a 33 10.5 is that they are uncommon, but as you are looking an another uncommon size - 32 11.5, It's a no brainer. I still don't think it's the best option, but if you can only run one set of tyres and did lots of road km's they ware at least the right size to work well off road, even of they aren't going to perform as well as a silverstone/swamper etc.

Steve.

[IN2DEP]

ok

3" lifted springs what will be better

31/10.5r15
32/11.5r15
33/10.5r15

And i do have a 1" bodylift sitting around here aswel so if i need to put it on i will ??
and yes i know witch one you picked steve

Hands up kids

[monley]

Gwagensteve wrote:

Because 32 11.5 is too short and too fat to have the right shaped footprint. Taller and narrower is always better than shorter and fatter, regardless of car or terrain.

Normally the only disadvantage of recommending a 33 10.5 is that they are uncommon, but as you are looking an another uncommon size - 32 11.5, It's a no brainer. I still don't think it's the best option, but if you can only run one set of tyres and did lots of road km's they ware at least the right size to work well off road, even of they aren't going to perform as well as a silverstone/swamper etc.

Steve.

Off topic a bit, but 31x10.5 r15 aren't really that great for a zook? Would something like a 31x9.5 r15 would be better?

[IN2DEP]

i always thought a fatter tyre would be better course theres more rubber on the ground, hense more traction ???

[christover1]

IN2DEP wrote:

i always thought a fatter tyre would be better course theres more rubber on the ground, hense more traction ???

A fatter tyre has to push more crud to move,
and often can't bite down through to traction,
like aqua planing.

More rubber on the ground is achieved by taller skinny tyres, too, without the losses from width.

[Gwagensteve]

Not necessarily.

This is quite a complex topic and not everyone agrees with me. I can say though that over the years I've been on enough trips with enough similar cars on the same terrain that I've seen what worked.

More rubber only equals more grip on surfaces where the rubber can grip the terrain- like on road, or on rock, so in summer, fat tyres are fine, but so are all terrains, and so are small tyres, because you can choose more lines.

On soft surfaces (so winter), it's the edges that do the work, and to get them to work you need to push them down into the soft surface. As you go to a bigger tyre, you have more rubber on the ground and that means less pressure, so the tyre doesn't dig into the surface, so you have less grip

Compare runners to footy boots on a muddy oval - that's the comparison, and shows the importance of ground pressure.

The next factor is that on soft terrain, a wider tyre has to clear more junk off the surface before the tyre can bite down. A narrow, tall tyre can generate more traction because there's not as much slippery surface material getting under the tyre, and when the mud is deeper, a narrower tyre saps less power when you are trying to spin them because you're not trying to push as much material out of the way - I have really noticed this with the Krawlers.

The last issue is directional control. A shorter, wider tyre has a very "square" footprint, so it doesn't really respond as well to steering. Think about a rudder on a boat - a rudder that was square won't work very well, but a rudder that is long and narrow turns the boat well. Taller, narrower tyres steer better and respond to throttle better - the car is easier to control when you are trying to get up a slippery track.

Steve.

PS Monkey - 31's aren't great in all honesty but it's sooo hard to get people to see an alternatives. a 235/85/16 or a 7.50 16 drives better, provides more clearance ( they are slightly taller) and is easier to fit due to the narrower profile tucking inside the guards, but 31's do perform acceptably. I wouldn't run them though. My personal suzuki's have run 7.50 16's, 34X9's, Q78's (which are still only 10" wide) and now the Krawlers.

[IN2DEP]

steve does it really matter with our 4wds tho ??
they weigh F-all so bigger wheels no matter what should do sierras wounders,

but, in away your saying the thinner tyres will cut through the mud straight to the hard stuff cause the weight of the car is all on one spot of the tyres not spread out on the wider tyres, yes ??

does that make sence ?? lol

[larry]

steves theory makes sense to me. the only thing i can see thats bad about them is theyre so skinny that they go right to the bottom of the rut, where fatter tyres would sit on the sides of the rut, so less clearance. but when your talking 34x9's its kind of irrelevant

[Gwagensteve]

IN2DEP wrote:

they weigh F-all so bigger wheels no matter what should do sierras wounders,

If you want a light car to have traction on surfaces with give, it needs high ground pressure. Putting a big tyre on a sierra can (and does) actually reduce traction in some circumstances - if it can't dig down a bit, it's just skating on top.

As you increase tyre size, you need to increase void ( make the tyre more aggressive) to ensure that ground pressure is retained.

Look at really light off road vehicles - ATV's, Dirt bikes, and UTV's - even though the might have large balloon-looking tyres, the tread has huge voids in it to generate ground pressure on a very light vehicle.

Compare this: to a 4WD tyre and you can see that that tyre is going to provide ground pressure on a light car.



It's the same reason that the southern rock bouncers do tho to a brand new 44" bogger:



To generate ground pressure on a light(ish) buggy with a VERY big tyre.

When you think about what makes a tyre work, it's "bite" and you can't have "bite" without ground pressure.

As an extreme example, this



Isn't going to have much "bite" on dirt because it will have very low ground pressure, with no edges to bite.

Interestingly, my F250 has very non-agressive road tyres on it, but it generates quite a bit of traction, even on clay, because it is heavy. Put the same tyre on a sierra and it would be useless because there isn't enough weight to push the large tread blocks into to dirt.

Larry - you are right, although with a narrow, tall tyre, you are more likely to be able to avoid getting in the rut in the first place due to better bite and better steering response. Unfortunately, where we drive, 9/34's fall into the bottom of the ruts far too often, which is why I am running 13.5's, and why, for instance, AJSR has left the back of his car narrow track - to stay up on the edge/crown of a rut.

Steve.

[IN2DEP]

so pretty much we need a really aggressive tread patten for zooks and put on a shit load of weight lol so the silverstone x-trem would be a good choise then what about the silverstone sport ?? Looks abit like a mudzilla/claw

I think ill stay with a 31 to be on the safe side,

[Gwagensteve]

The silverstone extreme is a very good choice in 31"

I think you can still get Simex MP Trekkers though - 32.1" tall, super narrow, 'pede tread

[suzi-fan-22]

got link to the car?

[IN2DEP]

Wouldnt it be unstable on hills with thinner tyres ?? Specialy lifted 3" like ill be

[Gwagensteve]

IN2DEP wrote:

Wouldnt it be unstable on hills with thinner tyres ?? Specialy lifted 3" like ill be

It won't be tyres that's making it unstable, it will be the track width which is down to your rims, and height, which is your lift.

You don't need 3" of spring lift to run a 31or a 7.50, so why would you make a car less stable than it could be. It's tyre diameter that gives you capability though traction and diff clearance.

A 2" BL will fit 31's or 7.50's with no suspension lift at all, with a lower centre of gravity than that tyre size with more suspension lift.

But if you are willing to do a virtual lift, Look at AJSR's build. 34's, no suspension lift, no body lift, and narrow track rear.

It's not hard to run a 31-32" tyre with very little added height.

Steve.

[Gwagensteve]

suzi-fan-22 wrote:

got link to the car?

No, I just google imaged "MP Trekker" and it popped up. It's a pretty generic japanese build.

Steve.

[Jackson]

Here is a good article about tyres, grip and all that http://www.autospeed.com/A_108915/cms/article.html

[3cyl]

I've only just removed the 7.50. 16 Insa turbos from the 6" rims on the LJ because of side slope instability. When running at the 12 to 14 psi they needed to be on the lighter vehicle they'd tend to fold under the rim on side slopes and I'd fall over. Now with 235. 85 r16s on the same 6" rims the car works much better. The 235s are Wrangler Kevlars (not much tread though). The insa were about 25mm taller btw.